According to some websites around the internet, there are "signature" trade marks to ensure authenticity of Manolo Blahnik's shoes, high-end luxury shoes popularized by "Sex and the City".

No embossed serial numbers.
Authentic white dust bags with black lettering. The box is also white and black.
Leather sole.

Manolo Blahnik & Marcia Patmos' 2011/12 Spring Sandles made from waste Tilapia Skins and other natural materials.

… more to come but here is an interesting case for the perception of materials verses the cost of these shoes.